1. Field of the Invention
The present invention relates to a method of manufacturing circuit modules. More particularly, the present invention relates to a method of manufacturing a circuit module having a frame soldered to a circuit substrate on which electronic components are mounted and terminals are soldered.
2. Description of the Prior Art
A circuit module such as an electronic tuner has a shield metal frame soldered along the periphery of a side surface of a dual side wiring substrate having an electronic component mounted on either side and terminals soldered thereon. Such a circuit module is formed according to the procedure shown in FIG. 1.
First, electronic components are mounted on one surface of a dual side wiring substrate. The electronic components are soldered by a reflow method to obtain high density. Then, electronic components are mounted on the other surface and soldered by a reflow method. Next, a terminal is connected in a mounting hole of the dual side wiring substrate, and the terminal is soldered by a soldering iron. Then, a frame for shielding is attached to the dual side wiring substrate along the side surface perimeter thereof and then soldered by a soldering iron. Finally, a cover is fitted above and below the shield frame.
This conventional manufacturing method has many processing steps. More specifically, in addition to the step of mounting electronic components onto each side of the dual side wiring substrate, the steps of soldering a terminal to the dual side wiring substrate and soldering the frame to the side surface of the wiring substrate are necessary. There is also a problem that soldering drops and flux are spattered during the soldering process thereby causing secondary defects. In a manufacturing method where a soldering iron is used, the soldering work is very difficult if there are electronic components near the portion which is to be soldered. Therefore, dead space is found at the periphery of the soldering portion, which inhibits increasing the packaging density.